Fuel injection apparatus



29, H- T. PYK ET AL FUEL. INJECTION APPARATUS 2 SHEETS-SHEET l` FiledOct. 29, 1946 All O 3 II 1N V EN TOR.

HERMAN THEoDoR PYK, BY HILMER GUNNAR cAMNER aufm/wey July 29, 1952 H. T.PYK ETAL FUEL INJECTION APPARATUS 2 SHEETS- SHEET 2 Filed Oct. 29, 1946FIG. 4

FIG. 5 v

INVENTOR. HERMAN THEODORE PYK BY HILYMER GUNNAR CAMNER AHORA/Eyatentecl' july 2.9, '1.95

UNITED STATES PATENT OFFICE v .2,605,141

FUEL INJECTION uAPPARA'IU Herman Theodor Pyk, Sa-ltsjo-Duvnas, and`Hilding Gunnar .Camnen Storangen, Sweden,

'.assignors kto .Aktiebolaget `Atlas Diesel, YSic'kla, near Stockholm,Sweden, a lcorD Oraidon of .Sweden Application 0ctober29,1946,SerialNor'OBgSG 7 Claims,

Our present invention relates to lcam driven Afuel injectionv apparatusand, ,'particularly, :to apparatus of this kind as used inconnectionwith internal combustion engines.

Diesel engines,especially high speeddiesel en- .gi-nes lwith solidinjection, generally operate in arough and uneven manner when theordinary injection devices are used, owing to the fact that ignitiontakes place more or less explosively. This rough running is a greatdisadvantage, becausefit not .only imposes extra 'mechanical strains Ionthe engine l`but also causes consid- -erable and disturbing noise.

In order to vimprove this rough running, attempts have been made todivide the fuel injection into 'itwofentirely separate phases, namely a,preliminary and a main injection, respec tively, Ywith lan intervalbetween the two. `The disadvantage fof this arrangement is, however,that after the first injection a certain amount of dripping occurs justas the fuel val-veis inthe act of closing, which rresults in smokyexhaust gases fand a poor fuel economy.

One object -of ourinvention is lto-provideim -provedmeansfor avoidingthese and othe-rdisadvantages -by effec-ting one continuous `'fuelinjection in two stages without interruption Abetweenthe'stages and sothat in vthe first vstage a preferably substantially constant Aandlrelative- 1ly-'lowinjection Apressure is maintained lWhilein the latterstage -the pressure isy increased to its maximum value. This rise ofthe-pressure in the second stage, .which represents the main injection,Amay be very rapid. This injection method results in a smooth and-silentengine operation without dripping, and hence thev deleterious resultsabove referred to are avoided. "For these and r`other purposes .weprovide Va fuel injection rapparatus comprising a pump producing va riseof the fuel pressure `to a moderate value, combined with an injectionvalve opening at saidmoderate. pressure, which is maintained at such .avalue as to keep said valve open dur- -the initial, stage of theinjection period,

said pumnproducing thenaJ further rise ofthe fuel pressure to a highvalue following upon saidmoderate pressure for effecting the second.stage f the iniectionperod. The injection valve is `designed so that,in conjunction With the pump, it not only produces the above describedtype of` injection, but further it maintains, vdurving'p'eripds between.the injection periods,.a fuel time interval between lthe pci-nt (Cl.29th-197.2)

pressure at the injection vvalve which is greater Athan the maximumpressure in ;the .engine cylinder, -thus preventing vany .possibility.of com.- bustiongases flowing'rback past the va'lve lwhich, Vifpermitted, would .cause .deposits of .carbon thereon.

Two Aembodiments `of :fuelfinjectioni..devices. .according to .the.invention are .illustrated :by-.Way of .examples in the vaccompanyingdrawings, :it

llbeing understood, .howeventhatyarious modicartions and .othercombinations of .thefillus-trated .elements Imay be madewithin.,the;;scopefof'the a modification of :the `ir-n'ecticnvalveshown-iin either yFigs.` 2 0r1i3'.

In the diagram .shown in Fig,

stant andmcderate fuel presenten!durinefthe :with increasing pressure.du 'bm-.c Auntil :the maximum .value .112 reached, the pressure l-isthen z.wholly y.or .partly relieved gwhen the .delivery `pressure :ofthe fuel pump drops.' The fuel injection thus proceeds finzione perioduninterruptedly .during fthe timevinterval a-c comprising a girststage;.a.-:b` .of frelatively low .-.and preferably lsubstantiallyconstant-pressure :and a 4second .stagebfc at'f'aapressurefifinfcreasingup to the #maximum ,.vajluie .and-,-repre sentir-ig-,themainfinjectiom1..-v

'ffhe quantity vof fuel'injected fduringeth'e .d-rst stage :should be.as ,small as :possible bu't should, however, .be distributed .overacertain perioden ablingaignition :to :take "place before athje secondstage of the linjection hascommenced Lori-Sim,.-

mediatelythereafter.

In .the :embodiments vof the inventionr-fillu'stra-ted intFigs. ;2 :and3 ythe fuel pump.v I consists driven in timed relation to the enginecrankshaft and cooperating with a cam follower roller 24. In theembodiment according to Fig. 2 the vmotion of the follower istransmitted directly to the pump plunger 2 and in the embodimentaccording to Fig. 3 through a rocker arm 25.

In the illustrated embodiments the fuel injection valve device comprisesan atomizer I0 and a spring-loaded fuel injection valve II controllingthe communication between the delivery end 'of the fuel pump and thecombustion chamber 48. The injection valve II is formed at the end of. apiston member I2 of a comparatively small diameter lapped in acylindrical guide 44 ending in a lower chamber I3 connected withthepressure chamber I9 of the fuel pump.

Inthe embodiment according to Fig. 2 the fuel pump is provided with ahead 4 in which a nonreturn pressure valve 6 loaded by a spring 5 isdisposed. The tension of said spring may be adjusted so that the valve 6opens ata higher fuel pressure than the injection Valve II. The head 4contains a further non-return valve 8 opening in the opposite direction.to the valve 6 and loaded by a spring 1. The valve 8 preferably opensat a pressure slightly above the maximum pressure in the combustionchamber 48 but lower than the pressure against which the injection'.valve IIl is designed 'to close. The pressure -chamber I8 of thefuelpump communicates with the chamber I3 in the fuel injection valvedevice 9 through a conduit I1, a passage I6, an annular vvduct 29, apassage 42,.a Valve 30 and a duct 21.

The valve 30 is displaceable and seated in a socket 2,0 and loaded by aweak spring 2I and opens towards the passage 21. The valve 3|) has apistonshaped pressure reducing portion 46 cooperating lwith acorresponding cylindrical .bore in the vsocket 2 0. VThe pressurechamber I8 of the fuel pump also communicates through a passage I9 withan upper chamber I5 in thevalve device 9. A piston member I4 of largervdiameterthan piston I2 is made integral with the piston member I2 andthe Vinjection valve II and lapped in a cylindrical guide 45. The wholeinjection valve unit II, I2, I4 isloaded'by a spring 22 tending to`.close the injection valve. The tension of the spring 22 may beadjusted by means of the screw 43. Y

' The fuel injection apparatus according to Fig. 2 operates in thefollowing manner:

During the rotation of the cam 23 in the direction. of the arrowinjection begins approximately Whenlthe point a1 ofthe cam v23 pressesagainst the roller 24 of the pump; the pump plunger 2 then covering thepassages 3. rThe'ramp Vportion a1-b1 of` theY cam. curve is Vdesigned tohave a slight rise' which is so adapted that the pressure during thisinjection stage is kept substantially constant at a moderate value.During this injection stage fuel is delivered from the pressure ChamberI8 past the valve 6. through the conduit 11. the passage I6, the duct 29and the passage I9 to the chamber I5, and, furthermore, through thepassage 42, past the valve 30 through the passage 21 to the lowerchamber I3. The moderate fuel pressure in the chambers I3 and I5 actingon the piston members I2 and I4 is sufficient to overcome the pressureof the spring 22 so that the injection valve Il is opened and fuel isinjected into the combustion chamber 48 at said moderate pressurethrough the nozzles of the atomizer I9. The following and contiguousramp portion bi-ci of the curve of the cam 23 is designed to have asharper rise so that the movement of the plunger 2 becomes more rapid,the result being that the fuel pressure rises owing to the'resistance inthe nozzles of the atomizer I0, and the main injection stage occurs atan increased pressure substantially according to the curve b-c indicatedin Fig. l. At the point c1 of the cam 23 the pressure in the pressurechamber I8 is relieved and consequently also the pressure in the chamberI5 acting on the larger piston I4 of the valve device 9. The load of thespring 22 is then suihcient to overcome the high pressure prevailing onthe smaller piston memberrl2 so that the injection valve I I isimmediately closed and surplus fuel in the chamber I3, the passages 21,42, I9, 29 and the conduit I1 is forced back past the valve 8 to thepump. However, the tension of the spring 1l controls the pressure in thechamber I3 and the passages communicating therewith so that it does notfall below the maximum combustion pressure of the engine cylinder andconsequently the combustion gases cannot enter the nozzles of theatomizeri I0. Furthermore, when return-flow of fuel from the chamber I3and the passage 21 occurs the pistonshaped portion 46 of the valve 38soon enters the bore in the socket 20 so that further return-flow isprevented. A suitable reduction of the pressure in the chamber I3 andthe passage 21 is, however, always obtained due to the pressure reducingaction of the portion 46 before the valve 39 is seated. Y

In some engines either the valve 30 or the valves E and 8 may bedispensed with. In the former case, however, the passage I9 should beconnected to the delivery end of the fuel pump before the valves 6 and 8instead of being connected to the duct 29. v

In the embodiment according to Fig. 3 the fuel pump I and the fuelinjection valve device 9 form a unit injector, which has the advantagethat the conduits or passages between the fuel pump and the injectionvalve are very much reduced in length. The parts of vthe'unit injectorillustrated in Fig. 3 which correspond to similar parts in theembodiment according to Fig. 2 have been indicated by the same referencevnumerals and are not described in detail.

' The pressure chamber I8 of the pump is in this case connected with thelower chamber I3.of the injection valve device 9 through a duct 41, apassage 33 and an annular duct 29 in the composite pump casing I, apassage 42, a non-return pressure reduction valve 30 provided with asuitablecylindrical pressure reduction portion 46, anda passage 21. Apassage I9 forms a direct communication between the pressure chamber'land the upper chamber I5 in the valve device 9. The injection valve unitII, I2, I4 is of the same design as in Fig. 2. A passage 38 serves todrain ezaking fuel from the space containing the spring l'The operationof the fuel injection apparatus according to Fig. 3 is similar to theoperation of tlie 'apparatus according -to Fi"g." 2, the onlydiierencebeing caused by 'the absence of the valves 46 land/8. Thu' s,ful injection starts at the iol'nt when the 'poi'nt 'di' on the cam 23reaches the rol-lerZ-d andam-oderate fuel pressure then acts o n themembers Al2 and I4 against the pressure of thespring 22, .the valve v3 0being opened and the injection valvek I I"being lifted from its seat so'that fuel 'isinjected at said moderate pressure through the nozzles ofthe etpmirill- Whaili-,e Peiniblf the 6 23 reachs the. gallery .th fslressue f p rsssre phamber I8. ,rises @liefe the iii? efsd numb pluhgerveleeitvanfijth 'increase Sistema ,ilihe i,lQeZlSvQf the. .at'o'mizerarid ,the main im' 8.0121911 stage. wmwst'vven the ivf 'flits b1.. and.-Gu .etree peint. .01. .tliefriessur .in the pressure chamberA l srelieved which immediately causes a pressure dr'p lintheduct 41, thepassage L33', the duct 29, lthe passage I9 andthe chamber 15. The spring22 isthen'capableiof closing the injection valve l l against thepressure prevail-ing in the chamber I3 which is simultaneously reducedsomewhat due to the return movement of the pressure reduction portion 46on the valve 30, which before the valve is seated increases the volumeof the space on the injection valve side of the valve 30. However, thisshould not decrease the pressure in space I3 to a value less thanthe'maximum engine cylinder pressure.

Fig. 4 illustrates a modification of the embodiment according to Fig. 2and is a section in a plane perpendicular to the section of Fig. 2. Inthis case afurther passage 26 containing a valve 2:8 land communicatingwith a passage 34 leading to the chamber I3 is provided in the valvedevice 9. The valve 28 which may have a piston-shaped pressure reducingportion 35 is disposed in a socket 36 and loaded by a spring 31. Thespringload on the valve 28 is, similarly tothe springload on the valve 8in Fig. 2, so dimensioned that the valve 28 is opened only at pressuresequal to or above the maximum combustion pressure.

The embodiment according to Fig. 2 modified according to Fig. 4 maypreferably be used when the valves 6 and 8 `are dispensed with since inthe modified embodiment the valves 30 and 28 may perform the functionsof the valves 6 and 8 raccording to Fig. 2, but in the case when boththe valves Grand 8 and 30, 28 are used a double safeguard is obtainedagainst pressure waves reaching the injection valve-after its closure.

In all described embodiments the valves 30 and/or 218 may ysometimes becarried out without the pressure reducing portion-s 46 and 3'5,respectively. The passages and valve 28 according to Fig. 4 may also beused in connection with Fig. 3.

It should be understood that the invention is not restricted to theembodiments above described and illustrated in the -drawings anddifferent modications and combinations of the elements may be madewithin the scope of the claims. yFor instance, the pump may bedifferently designed, and the pressure relief achieved by means of theillustrated form of Dump plunger may be achieved by other pressurerelieving means common in the art.

What we claim is:

v1. In a fuel injection system for injecting fuel to a combustionchamber, a plunger pump having a pressure releasing cut-off fordetermining .the end of the effective -discharge stroke of the plungeryand ycam means comprising two contiguous ramp portions having differentrates of Y c' isefor causing ueiiveriybf Yfuel''from tiie'puuip mira-uy'ai; relairway, `sifowrafe 'followed Wimpie interruption by delivery 'athigher rate, whereby sureffo'r'preinjection and thereafter at-highpresav sure for main injection, anda fuel injectionva'lve land havinglajsprinfg load for closing#the"valve,

avj'irl'rs't pressure responsive means and .a 'Second pressureresponsivemeans to which fuel underv pressurelfrom Asaidfp'urnp isadmitted, 'sa-id "pres-I` sure 2respons-ive means together being'operative toy overcome said spring load and open said valve under theinfluencenf said 'moderate pressure and 'to maintain vthe valve openIunder the fine unce Aof ytheI'fol lowing high pressure, and means forv-releasing vthe pressure acting on yoneo'ff said pressure fresfporjsivemeans while maintaining high pressure on the other of said pressureAfre'- sponsive means when pump pressure is released 'by said pumpcut-off, said spring load lbeing sufficient to close said valve againstthe high pressure maintained on said other pressure responsive mean-s.

2. A system as set forth in claim 1 in which said injection valvecompri-ses two piston portions of different area each in communicationwith a different pressure chamber, and said valve device includespassages for separately supplying fuel to said chambers.

3. A system as set forth in claim 2` in which pres-sure is released bythe pump cut-off from the piston portion of larger area.

4. A system as set forth in claim 3 in which said valve device in-cludesa second valve located in the passage leading to the chamber with whichthe piston portion of smaller `area communicates, said valve beingoperative to maintain pressure in the last mentioned chamber after pumppressure has been released by said cut-01T.

5. A fuel injection valve comprising a valve housing a portion of whichforms a fuel injection nozzle, a fuel injection opening in said nozzle,a fuel supply passage in said housing leading to said opening, aone-piece portion of the housing having at least one bore with largediameter and one bore with small diameter, a main valve membercontrolling `the opening and movable in the housing and having `at leastone plunger type guiding portion with large diameter forming a fluidtight seal in said large bore and one plunger type guidingportion withsm-all diameter forming a uid tight seal in said small bore, and anauxiliary non-return valve in the housing disposed in said passageleading to the nozzleopening.

`6. A fuel injection valve comprising a valve housing a portion :ofwhich forms a fuel injection nozzle, a fuel injection opening in saidnozzle, a fuel supply passage in said housing lead-ing to said opening,a one-piece portion of the housing having at least one bore with largediameter and one bore with small diameter, a main valve membercontrolling the opening and movable in the housing and having at leastone plunger type guiding portion with large diameter forming a fluidtight seal in said large bore and one plunger type guiding portion withsmall diameter forming a fluid tight seal in said small bore, and anauxiliary valve in said one-piece portion of the housing disposed insaid passage leading to the nozzle opening.

A'7. Afuel injection Valve comprising' a Valve diameter forming vaudtight s'eal'in said large',

bore and one-plunger type guiding portion 'with small diameterV formingva uid tight seal in saidsmall bore and movable' in the housing againstsaid spring load upon fuel press-ure actuation of said large and smallplunger type portions, a space in the housingl communicating with saidfuel passage vand exposing the large plunger type portion to fuelpressure, a further space `in the housingcommunicating with thefuelpassage and exposing the small plunger type' portion tofuel pressurebandan auxiliary non-return valve in saidonefpiece-portion of the housingdisposed 8- in the fuel passage leading to the nozzle openingbetweensaid spaces. i

v HERMAN TI-IEODOR HILDING GUNNAR CAMNER.

, REFERENCES CITED The following references are Aof record in the fileof this patent: l'

A UNITED STATES PATENTS Number v Name Date 1,834,061 f Joachim '.V Dec.1, 1931 1,907,696 Woolson May 9, 1933 2,012,086 Mock Aug. 20, 1935 152,090,781 Camner Aug. 24, 1937 2,223,755 Dillstrom Dec. 3, 19402,306,364 Skaredoff Dec. 22, 1942 2,380,148 j Camner July 10, 1945FOREIGN PATENTS z. Number Y Country Date.

V248,212 Italy May 11, 1926

